Purification of acrylic acid and methacrylic acid

US5831124A · kind A · utility

Assignee

• BASF SE

Inventors

• Otto Machhammer · Mannheim, DE
• Albrecht Dams · Monsheim, DE
• Bernd Eck · Viernheim, DE
• Theo Proll · Bad Dürkheim, DE

Key dates

• Filing date: Feb 12, 1997
• Grant date: Nov 3, 1998
• Expiry date: Feb 12, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/43
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Acrylic acid or methacrylic acid is purified by PA1 (a) subjecting a mixture comprising the acrylic acid or methacrylic acid to a sharply defined separation process essentially in the absence of an organic solvent, with the composition of the phase in which the acrylic acid or methacrylic acid accumulates remaining essentially constant when the composition of the other phases participating in the mass transfer changes, then taking off this phase and PA1 (b) subjecting at least a part of the remaining phase from stage(a) to a less sharply defined separation process and PA1 (c) feeding one of the phases formed in stage (b) to the sharply defined separation process in stage (a). In addition, the invention provides a process for preparing acrylic acid or methacrylic acid which includes the abovementioned purification process.